Field
Embodiments described herein relate generally to a device for transferring electrical power using light to achieve electrical isolation between a powered circuit and a powering circuit that provides power to the powered circuit, and, more particularly, to an optical power transfer (OPT) device transmitting light to multiple photovoltaic (PV) devices that are electrically connected in series, and the multiple photovoltaic (PV) devices are arranged such that the light propagates through the depletion regions of the PV devices without first propagating through the conduction region (e.g., the p-doped or n-doped regions adjacent to the depletion regions) of the PV devices.
Description of the Related Art
Optical power transfer (OPT), also referred to photonic power, has several advantages over electrical power transfer systems. First, OPT provides electrical isolation between a circuit that supplies power (i.e., the powering circuit) and a power consuming circuit (i.e. the powered circuit). Second, OPT can be used to transfer power via optical fiber or free space propagation into remote or inaccessible environments (e.g., into oil wells or outer space) or into environments were electrical power transfer would be dangerous (e.g., environments where a spark could initiate an explosion or were electrical power transfer increases risks due to creating conduction paths to the sensitive components during a lighting strike). The method and apparatus discussed herein focus primarily on the first advantage of avoiding noise from ground loops and avoiding electromagnetic interference (EMI).
In OPT, an optical source converts, at a first location, electrical energy into optical energy, and transmits the optical energy to a second location. At the second location, the optical energy has propagated from the optical source to a photovoltaic (PV) cell that converts the light back into electrical energy. OPT is similar to optical isolators that can also be used to interrupt ground loops and minimize EMI while enabling signals to be sent between two electrically isolated circuits. Unlike general optical-isolation circuits (e.g., photo-couplers) for which energy consumption and efficiency can be secondary or even tertiary significance, OPT systems are primarily concerned with energy transfer, and therefore efficiency of the energy transfer processes is of primary importance. Generally, conventional OPT systems can be bulky and can have suboptimal efficiency.